Technical Disclosure
The present disclosure relates to a light regulating apparatus and a light regulating method thereof. More particularly, the present disclosure relates to a light regulating apparatus and a light regulating method thereof for regulating a load current.
Description of Related Art
In recent years, since a manufacture technology of light emitting diode (LED) has been developed, a luminance and an efficiency of LED have increased greatly. Therefore, LED has replaced incandescent lamp as a new light component and has been applied in various devices, e.g., household lighting device, handheld lighting device, automotive lighting device, backlight source of liquid crystal panel, traffic light, etc. However, since the characteristic of LED is different from the characteristic of incandescent lamp, the light regulating circuit applied for LED is different from the light regulating circuit applied for incandescent lamp.
In conventional technology, in order to drive a load circuit with several LED series, it is usually to couple a voltage regulator or a current regulator to the load circuit so as to stabilize an operating current of LED series by the characteristic of constant current of the voltage regulator or the current regulator. For example, a converter is utilized to convert a direct voltage or an alternating voltage into a constant direct voltage and an operating voltage applied to the load circuit is generated by providing the constant direct voltage to the voltage regulator or the current regulator.
FIG. 1 depicts a conventional light-regulating apparatus. As shown in FIG. 1, in order to rapidly regulate a current magnitude or a voltage magnitude outputted from the current regulator or the voltage regulator, the conventional approach is to couple capacitors C1-Cn to an output terminal of the current regulator or the voltage regulator in parallel, in which capacitors C1-Cn are coupled to the output terminal of the current regulator or the voltage regulator through switch components T1-Tn, respectively. First, capacitors C1-Cn are charged to a pre-determined voltage through an output voltage Vo of the current regulator or the voltage regulator. Next, capacitors C1-Cn are selected by controlling each switch component to be turned on or turn off so as to output a rated operating voltage to the load circuit (e.g., LED). Accordingly, rapidly regulating the current magnitude of LED is implemented.
However, the disadvantage of the aforementioned approach is that regulating the current magnitude is inflexible. By coupling one capacitor to the current regulator or the voltage regulator to get one current magnitude, the current magnitude applied to LED is difficult to be regulated continuously.
Moreover, another conventional approach for regulating the current magnitude of LED is to couple a linear regulator to LED series in series and regulate the current through LED series by regulating the linear regulator. However, in this approach, the conversion efficiency of the converter is bad.